WIMBLEDON, England — Wimbledon will crown a first-time winner and a first-time Grand Slam champion on Saturday. That will come as no surprise after a tournament inundated with upsets.

Tuesday's quarterfinals produced an unlikely quartet, none more so than Kirsten Flipkens of Belgium, who upset 2011 Wimbledon champion Petra Kvitova of the Czech Republic 4-6, 6-3, 6-4. Sabine Lisicki, Agnieszka Radwanska and Marion Bartoli round out the final four.

"It's ridiculous," an incredulous Flipkens told BBC when she came off the court. The No. 20 seed suffered from blood clots in her legs and had fallen so low in the rankings last year she couldn't even enter Wimbledon's qualifying event.

"The people believing in me, I can count on one hand," Flipkens said. "It's amazing."

While Flipkens was winning, one of Belgium's best, Kim Clijsters was at home in America watching.

"Still drying my eyes," Clijsters tweeted. "So proud of how (Flipkens) handled the big occasion for the first time!"

Flipkens will face off against 2007 runner-up Bartoli, the No. 15 seed from France.

Lisicki suffered no letdown after blasting No. 1 Serena Williams out of the tournament. The 23rd-seed from Germany beat unseeded Kaia Kanepi of Estonia 6-3, 6-3 to reach the All-England Club semifinals for the third time.

Her next opponent is No. 4 seed Radwanska, who defeated No. 6 seed Li Na of China 7-6 (7-5), 4-6, 6-2. The entertaining match featured two rain delays, an injury timeout and plenty of creative shotmaking. Poland's Radwanska, the highest seed remaining, is seeking her second straight Wimbledon final.

Bartoli held off No. 17 seed Sloane Stephens 6-4 7-5. The 20-year-old American was gunning for her second Grand Slam semifinal of the season after reaching the last four at the Australian Open.

Lisicki became the oddsmakers' choice after Williams' 34-match winning streak, even though many feared how she would bounce back after her epic upset.

"I was ready today," Lisicki said. "I knew from the past, out of experience, that I needed to make the switch quickly to be ready, and that's what I did."

Lisicki's game seems well-suited to grass — especially her superior serve — and she has showed surprisingly good movement throughout the tournament.

"I've had some great challenges on the way to the semis, and now I'm ready for the semis," Lisicki said.

Kanepi, the Estonian who advanced to the quarterfinals by defeating Britain's Laura Robson, said she couldn't match her play from that victory. She had 13 winners and 23 unforced errors against Lisicki over the 65-minute match and fell to 0-5 in Grand Slam quarterfinals.

"I thought (when) I tried to attack in previous matches, I hit winners and did well, but today I was missing a lot," Kanepi said. "But on grass there is no Plan B. I just have to go for my shots. If there is a ball, I have to hit it."

Radwanska moved one win from her second consecutive Wimbledon final, putting Li away on the eighth match point. Radwanska called for a medical timeout after the second set so a trainer could work on her right thigh. Up 5-2 in the third set, she called for the trainer again for a quick treatment on both legs.

"Too much tennis the last few days," she said. "I was struggling with that. Otherwise, I think it's a good problem to have.

"... If it's the end of a Grand Slam you don't really think about the pain or anything else. You just fight until the end. That's what I was doing today."

With Radwanska advancing, Poland is guaranteed a semifinalist in both the men's and women's draws. On Wednesday, Jerzy Janowicz plays Lukasz Kubot in an all-Polish men's quarterfinal.

"I kind of started it," said Radwanska, who last year became the first Polish woman to reach a Grand Slam final since 1939, before falling to Williams. "It's great to have, now, the guys doing very, very well. Especially Jerzy. He's a young, great, upcoming player. I believe he's also going to be top-10. This is, for sure, not his last quarterfinal of a Grand Slam."

Bartoli earned the ire of the Court 1 crowd when droplets of rain started to fall and she complained about the court conditions with Stephens serving at 4-5, deuce. When they returned, Bartoli won two quick points to seal the set.

"I didn't really get why the crowd was so against me at that point," Bartoli said. "Already, the courts were a bit slippery even when it's dry. When it's wet, it can get dangerous. I didn't want to stop the match for no reason. It was a precaution. I saw the crowd go against me but I'm just glad to be moving on to the semifinals."

Stephens said it would have been nice to finish the game before the break, which lasted about 2 ½ hours.

"Coming back and serving at deuce, that's always going to be tough for anyone," she said.